Polymer-Plastics Technology and Materials
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2020
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IF 0
Guorong Qiu,Wenshi Ma,Li Wu
The thermoplastic and low dielectric constants polyimides were introduced. The polyimides were prepared by pyromellitic dianhydride (PMDA) or 4,4ʹ-(4,4ʹ-Isopropylidenediphenoxy)diphthalic anhydride (BPADA) as anhydride monomer and 4,4ʹ-oxydianiline (ODA) or 2,2-bis(4-(4-aminephenoxy)phenyl)propane (BAPP) as amine monomer. The polyimides were well characterized by FT-IR, thermogravimetric analysis, dynamic thermomechanical analysis, dielectric measurement, and tensile test. The dielectric constants were 2.32–2.95 compared with 3.10 of ODA-PMDA polyimide, while partly polyimides were thermoplastic. The results indicated anhydride monomers, containing lateral methyl groups, made polyimides become thermoplastic. The results of molecular simulations via Materials Studio also proved this conclusion.
研究领域:
材料科学
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化学工程
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产品关联
DOI
EUROPEAN POLYMER JOURNAL
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2022
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IF 5.546
Gaojie Wu,Zichen Wang,Yucheng Zi,Shengli Qi,Guofeng Tian,Dezhen Wu
In order to prepare polyimide resins with excellent melt processing properties and high transmittance, a series of thermoplastic fluorinated polyimide resins was prepared by copolycondensation of the flexible dianhydride monomer 4,4′-(4,4′-isopropyldiphenoxy)bis(phthalic anhydride) (BPADA) and the fluorinated diamine monomer 2,2′-bis(trifluoromethyl)benzidine (TFMB) with different contents of fluorinated dianhydride 4,4′-(hexafluoroisopropyl)diphthalic anhydride (6FDA) or cyclobutanetetracarboxylic dianhydride (CBDA) via chemical imidization. The effects of the third monomer content on the melt processing properties, optical properties, heat resistance, and mechanical properties of the polyimide resins were systematically investigated. The minimum melt viscosity of the PI resins reached 630 Pa·s below 400 °C. The transmittance at 450 nm of PI sheets prepared by compression molding reached 77%, and the color was significantly lighter than the commercial thermoplastic resin ULTEM, indicative of excellent processability and optical properties. Besides, the PI resins displayed outstanding thermal performance with glass transition temperatures ranging from 224 °C to 242 °C, 5% weight loss temperatures higher than 520 °C in a nitrogen atmosphere, and coefficients of thermal expansion of 51.45–68.97 ppm/K. Moreover, the PI sheets possessed tensile strengths of 88.4–104.7 MPa.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
POLYMER
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2022
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IF 4.432
Hongyu Jiang,Hong Zhang,Yaqing Wen,Liyun Tan,Xingzhong Fang,Guofei Chen
Mixed isopropylidenebis(1,4-phenylene-oxy) bis(phthalic anhydride)s with different ratios ( Mixed-BPADA 1-3 ) were synthesized successfully via aromatic nucleophilic substitution from nitrophthalonitrile and bisphenol A. The corresponding copolyetherimides (CoPEIs) were prepared with two representative aromatic diamines (4,4′-oxydianiline (4,4′-ODA) and m -phenylenediamine ( m -PDA)) via two-step procedure and chemical imidization. CoPEIs showed T g s from 222 to 256 °C and T d5% s from 486 to 505 °C in argon, good mechanical properties (tensile moduli of 2.5–2.9 GPa, tensile strengths of 69–96 MPa, and elongations at break of 3.3–6.3%), and good solubility. With the introduction of 3-substituted phthalimide unit, CoPEIs displayed higher T g values, lower elongations, better solubility and larger d -spacings. The rheological properties of thermoplastic polyimide resins based on the Mixed-BPADA were investigated. CoPEI-b series displayed good melt processibility, and the CoPEI-3b derived from Mixed-BPADA 3 and m -PDA had the lowest melt viscosity among the copolymers . Compared to isomeric PEIs derived from BPADA isomers, CoPEIs displayed lower melt viscosities, indicating that the melt processibility had been greatly improved.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
Journal of Macromolecular Science Part A-Pure and Applied Chemistry
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2023
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IF 2.5
Guorong Qiu,Wenshi Ma
The polyimides were prepared by pyromellitic dianhydride (PMDA) or 4,4'-(4,4'-Isopropylidenediphenoxy)diphthalic anhydride (BPADA) as dianhydride monomer and 1,4-bis(4-aminophenoxy)benzene(TPE-Q) or 1,3-bis(4-aminophenoxy)benzene(TPE-R) as diamine monomer. The polyimides were well characterized by FT-IR, thermogravimetric analysis, dynamic thermomechanical analysis, dielectric measurement and tensile test. The flexibility of polyimide molecular chain was judged by the comparison of molecular volumes, molecular length and conformation transition energy through molecular simulations.
研究领域:
材料科学
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高分子化学
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介电材料
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热分析
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DOI
高影响因子
危险品化学品经营许可证（带存储）